Lagg issues

Hi,

I've had these lag issues for some months now, if not a year nonstop..
My fps is fine the whole time. But after 22.00 all the crap starts. I start lagging like the added video. It starts with small lags, but it gets worse and worse.
If I log off my windows account, and back in. It's gone. After a while it returns.
It's weird lag, because it's constantly like that.
My FPS is fine and I aint downloading or uploading anything on the background.
Hardware is up to date
Anyone has a clue?

that dosent look internet related lol, i have that on my laptop/pc sometimes, heres a few things to check;

GPU- cant speak for nvidia (never used yet) but if its amd, open control panel, go to the overclock section which shows what the gpu is running at, see what it is when wow runs fine, and have it minimized/easily accessable. when the lag starts have a look again, eg.